| 1 | /* Target-dependent code for PowerPC systems using the SVR4 ABI |
| 2 | for GDB, the GNU debugger. |
| 3 | |
| 4 | Copyright 2000, 2001, 2002 Free Software Foundation, Inc. |
| 5 | |
| 6 | This file is part of GDB. |
| 7 | |
| 8 | This program is free software; you can redistribute it and/or modify |
| 9 | it under the terms of the GNU General Public License as published by |
| 10 | the Free Software Foundation; either version 2 of the License, or |
| 11 | (at your option) any later version. |
| 12 | |
| 13 | This program is distributed in the hope that it will be useful, |
| 14 | but WITHOUT ANY WARRANTY; without even the implied warranty of |
| 15 | MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the |
| 16 | GNU General Public License for more details. |
| 17 | |
| 18 | You should have received a copy of the GNU General Public License |
| 19 | along with this program; if not, write to the Free Software |
| 20 | Foundation, Inc., 59 Temple Place - Suite 330, |
| 21 | Boston, MA 02111-1307, USA. */ |
| 22 | |
| 23 | #include "defs.h" |
| 24 | #include "gdbcore.h" |
| 25 | #include "inferior.h" |
| 26 | #include "regcache.h" |
| 27 | #include "value.h" |
| 28 | #include "gdb_string.h" |
| 29 | |
| 30 | #include "ppc-tdep.h" |
| 31 | |
| 32 | /* round2 rounds x up to the nearest multiple of s assuming that s is a |
| 33 | power of 2 */ |
| 34 | |
| 35 | #undef round2 |
| 36 | #define round2(x,s) ((((long) (x) - 1) & ~(long)((s)-1)) + (s)) |
| 37 | |
| 38 | /* Pass the arguments in either registers, or in the stack. Using the |
| 39 | ppc sysv ABI, the first eight words of the argument list (that might |
| 40 | be less than eight parameters if some parameters occupy more than one |
| 41 | word) are passed in r3..r10 registers. float and double parameters are |
| 42 | passed in fpr's, in addition to that. Rest of the parameters if any |
| 43 | are passed in user stack. |
| 44 | |
| 45 | If the function is returning a structure, then the return address is passed |
| 46 | in r3, then the first 7 words of the parametes can be passed in registers, |
| 47 | starting from r4. */ |
| 48 | |
| 49 | CORE_ADDR |
| 50 | ppc_sysv_abi_push_dummy_call (struct gdbarch *gdbarch, CORE_ADDR func_addr, |
| 51 | struct regcache *regcache, CORE_ADDR bp_addr, |
| 52 | int nargs, struct value **args, CORE_ADDR sp, |
| 53 | int struct_return, CORE_ADDR struct_addr) |
| 54 | { |
| 55 | int argno; |
| 56 | /* Next available general register for non-float, non-vector arguments. */ |
| 57 | int greg; |
| 58 | /* Next available floating point register for float arguments. */ |
| 59 | int freg; |
| 60 | /* Next available vector register for vector arguments. */ |
| 61 | int vreg; |
| 62 | int argstkspace; |
| 63 | int structstkspace; |
| 64 | int argoffset; |
| 65 | int structoffset; |
| 66 | struct type *type; |
| 67 | int len; |
| 68 | char old_sp_buf[4]; |
| 69 | CORE_ADDR saved_sp; |
| 70 | struct gdbarch_tdep *tdep = gdbarch_tdep (current_gdbarch); |
| 71 | |
| 72 | greg = 3; |
| 73 | freg = 1; |
| 74 | vreg = 2; |
| 75 | argstkspace = 0; |
| 76 | structstkspace = 0; |
| 77 | |
| 78 | /* If the function is returning a `struct', then the first word |
| 79 | (which will be passed in r3) is used for struct return address. |
| 80 | In that case we should advance one word and start from r4 |
| 81 | register to copy parameters. */ |
| 82 | if (struct_return) |
| 83 | { |
| 84 | regcache_raw_write_signed (regcache, tdep->ppc_gp0_regnum + greg, |
| 85 | struct_addr); |
| 86 | greg++; |
| 87 | } |
| 88 | |
| 89 | /* Figure out how much new stack space is required for arguments |
| 90 | which don't fit in registers. Unlike the PowerOpen ABI, the |
| 91 | SysV ABI doesn't reserve any extra space for parameters which |
| 92 | are put in registers. */ |
| 93 | for (argno = 0; argno < nargs; argno++) |
| 94 | { |
| 95 | struct value *arg = args[argno]; |
| 96 | type = check_typedef (VALUE_TYPE (arg)); |
| 97 | len = TYPE_LENGTH (type); |
| 98 | |
| 99 | if (TYPE_CODE (type) == TYPE_CODE_FLT |
| 100 | && ppc_floating_point_unit_p (current_gdbarch)) |
| 101 | { |
| 102 | if (freg <= 8) |
| 103 | freg++; |
| 104 | else |
| 105 | { |
| 106 | /* SysV ABI converts floats to doubles when placed in |
| 107 | memory and requires 8 byte alignment */ |
| 108 | if (argstkspace & 0x4) |
| 109 | argstkspace += 4; |
| 110 | argstkspace += 8; |
| 111 | } |
| 112 | } |
| 113 | else if (len == 8 |
| 114 | && (TYPE_CODE (type) == TYPE_CODE_INT /* long long */ |
| 115 | || (!ppc_floating_point_unit_p (current_gdbarch) |
| 116 | && TYPE_CODE (type) == TYPE_CODE_FLT))) /* double */ |
| 117 | { |
| 118 | if (greg > 9) |
| 119 | { |
| 120 | greg = 11; |
| 121 | if (argstkspace & 0x4) |
| 122 | argstkspace += 4; |
| 123 | argstkspace += 8; |
| 124 | } |
| 125 | else |
| 126 | { |
| 127 | if ((greg & 1) == 0) |
| 128 | greg++; |
| 129 | greg += 2; |
| 130 | } |
| 131 | } |
| 132 | else if (!TYPE_VECTOR (type)) |
| 133 | { |
| 134 | if (len > 4 |
| 135 | || TYPE_CODE (type) == TYPE_CODE_STRUCT |
| 136 | || TYPE_CODE (type) == TYPE_CODE_UNION) |
| 137 | { |
| 138 | /* Rounding to the nearest multiple of 8 may not be necessary, |
| 139 | but it is safe. Particularly since we don't know the |
| 140 | field types of the structure */ |
| 141 | structstkspace += round2 (len, 8); |
| 142 | } |
| 143 | if (greg <= 10) |
| 144 | greg++; |
| 145 | else |
| 146 | argstkspace += 4; |
| 147 | } |
| 148 | else |
| 149 | { |
| 150 | if (len == 16 |
| 151 | && TYPE_CODE (type) == TYPE_CODE_ARRAY |
| 152 | && TYPE_VECTOR (type)) |
| 153 | { |
| 154 | if (vreg <= 13) |
| 155 | vreg++; |
| 156 | else |
| 157 | { |
| 158 | /* Vector arguments must be aligned to 16 bytes on |
| 159 | the stack. */ |
| 160 | argstkspace += round2 (argstkspace, 16); |
| 161 | argstkspace += 16; |
| 162 | } |
| 163 | } |
| 164 | else if (len == 8 |
| 165 | && TYPE_CODE (type) == TYPE_CODE_ARRAY |
| 166 | && TYPE_VECTOR (type)) |
| 167 | { |
| 168 | if (greg <= 10) |
| 169 | greg++; |
| 170 | else |
| 171 | { |
| 172 | /* Vector arguments must be aligned to 8 bytes on |
| 173 | the stack. */ |
| 174 | argstkspace += round2 (argstkspace, 8); |
| 175 | argstkspace += 8; |
| 176 | } |
| 177 | } |
| 178 | } |
| 179 | } |
| 180 | |
| 181 | /* Get current SP location */ |
| 182 | saved_sp = read_sp (); |
| 183 | |
| 184 | sp -= argstkspace + structstkspace; |
| 185 | |
| 186 | /* Allocate space for backchain and callee's saved lr */ |
| 187 | sp -= 8; |
| 188 | |
| 189 | /* Make sure that we maintain 16 byte alignment */ |
| 190 | sp &= ~0x0f; |
| 191 | |
| 192 | /* Update %sp before proceeding any further */ |
| 193 | write_register (SP_REGNUM, sp); |
| 194 | |
| 195 | /* write the backchain */ |
| 196 | store_unsigned_integer (old_sp_buf, 4, saved_sp); |
| 197 | write_memory (sp, old_sp_buf, 4); |
| 198 | |
| 199 | argoffset = 8; |
| 200 | structoffset = argoffset + argstkspace; |
| 201 | freg = 1; |
| 202 | greg = 3; |
| 203 | vreg = 2; |
| 204 | |
| 205 | /* Fill in r3 with the return structure, if any */ |
| 206 | if (struct_return) |
| 207 | { |
| 208 | write_register (tdep->ppc_gp0_regnum + greg, struct_addr); |
| 209 | greg++; |
| 210 | } |
| 211 | |
| 212 | /* Now fill in the registers and stack... */ |
| 213 | for (argno = 0; argno < nargs; argno++) |
| 214 | { |
| 215 | struct value *arg = args[argno]; |
| 216 | char *val = VALUE_CONTENTS (arg); |
| 217 | type = check_typedef (VALUE_TYPE (arg)); |
| 218 | len = TYPE_LENGTH (type); |
| 219 | |
| 220 | if (TYPE_CODE (type) == TYPE_CODE_FLT |
| 221 | && ppc_floating_point_unit_p (current_gdbarch)) |
| 222 | { |
| 223 | if (freg <= 8) |
| 224 | { |
| 225 | ULONGEST regval; |
| 226 | if (len > 8) |
| 227 | printf_unfiltered ( |
| 228 | "Fatal Error: a floating point parameter #%d with a size > 8 is found!\n", argno); |
| 229 | regval = extract_unsigned_integer (val, len); |
| 230 | write_register (FP0_REGNUM + freg, regval); |
| 231 | freg++; |
| 232 | } |
| 233 | else |
| 234 | { |
| 235 | /* SysV ABI converts floats to doubles when placed in |
| 236 | memory and requires 8 byte alignment */ |
| 237 | /* FIXME: Convert floats to doubles */ |
| 238 | if (argoffset & 0x4) |
| 239 | argoffset += 4; |
| 240 | write_memory (sp + argoffset, val, len); |
| 241 | argoffset += 8; |
| 242 | } |
| 243 | } |
| 244 | else if (len == 8 |
| 245 | && (TYPE_CODE (type) == TYPE_CODE_INT /* long long */ |
| 246 | || (!ppc_floating_point_unit_p (current_gdbarch) |
| 247 | && TYPE_CODE (type) == TYPE_CODE_FLT))) /* double */ |
| 248 | { |
| 249 | if (greg > 9) |
| 250 | { |
| 251 | greg = 11; |
| 252 | if (argoffset & 0x4) |
| 253 | argoffset += 4; |
| 254 | write_memory (sp + argoffset, val, len); |
| 255 | argoffset += 8; |
| 256 | } |
| 257 | else |
| 258 | { |
| 259 | ULONGEST regval; |
| 260 | if ((greg & 1) == 0) |
| 261 | greg++; |
| 262 | regval = extract_unsigned_integer (val, 4); |
| 263 | write_register (tdep->ppc_gp0_regnum + greg, regval); |
| 264 | regval = extract_unsigned_integer (val + 4, 4); |
| 265 | write_register (tdep->ppc_gp0_regnum + greg + 1, regval); |
| 266 | greg += 2; |
| 267 | } |
| 268 | } |
| 269 | else if (!TYPE_VECTOR (type)) |
| 270 | { |
| 271 | char val_buf[4]; |
| 272 | if (len > 4 |
| 273 | || TYPE_CODE (type) == TYPE_CODE_STRUCT |
| 274 | || TYPE_CODE (type) == TYPE_CODE_UNION) |
| 275 | { |
| 276 | write_memory (sp + structoffset, val, len); |
| 277 | store_unsigned_integer (val_buf, 4, sp + structoffset); |
| 278 | structoffset += round2 (len, 8); |
| 279 | } |
| 280 | else |
| 281 | { |
| 282 | memset (val_buf, 0, 4); |
| 283 | memcpy (val_buf, val, len); |
| 284 | } |
| 285 | if (greg <= 10) |
| 286 | { |
| 287 | ULONGEST regval = extract_unsigned_integer (val_buf, 4); |
| 288 | write_register (tdep->ppc_gp0_regnum + greg, regval); |
| 289 | greg++; |
| 290 | } |
| 291 | else |
| 292 | { |
| 293 | write_memory (sp + argoffset, val_buf, 4); |
| 294 | argoffset += 4; |
| 295 | } |
| 296 | } |
| 297 | else |
| 298 | { |
| 299 | if (len == 16 |
| 300 | && TYPE_CODE (type) == TYPE_CODE_ARRAY |
| 301 | && TYPE_VECTOR (type)) |
| 302 | { |
| 303 | char *v_val_buf = alloca (16); |
| 304 | memset (v_val_buf, 0, 16); |
| 305 | memcpy (v_val_buf, val, len); |
| 306 | if (vreg <= 13) |
| 307 | { |
| 308 | regcache_cooked_write (current_regcache, |
| 309 | tdep->ppc_vr0_regnum + vreg, |
| 310 | v_val_buf); |
| 311 | vreg++; |
| 312 | } |
| 313 | else |
| 314 | { |
| 315 | write_memory (sp + argoffset, v_val_buf, 16); |
| 316 | argoffset += 16; |
| 317 | } |
| 318 | } |
| 319 | else if (len == 8 |
| 320 | && TYPE_CODE (type) == TYPE_CODE_ARRAY |
| 321 | && TYPE_VECTOR (type)) |
| 322 | { |
| 323 | char *v_val_buf = alloca (8); |
| 324 | memset (v_val_buf, 0, 8); |
| 325 | memcpy (v_val_buf, val, len); |
| 326 | if (greg <= 10) |
| 327 | { |
| 328 | regcache_cooked_write (current_regcache, |
| 329 | tdep->ppc_ev0_regnum + greg, |
| 330 | v_val_buf); |
| 331 | greg++; |
| 332 | } |
| 333 | else |
| 334 | { |
| 335 | write_memory (sp + argoffset, v_val_buf, 8); |
| 336 | argoffset += 8; |
| 337 | } |
| 338 | } |
| 339 | } |
| 340 | } |
| 341 | |
| 342 | target_store_registers (-1); |
| 343 | return sp; |
| 344 | } |
| 345 | |
| 346 | /* Until November 2001, gcc was not complying to the SYSV ABI for |
| 347 | returning structures less than or equal to 8 bytes in size. It was |
| 348 | returning everything in memory. When this was corrected, it wasn't |
| 349 | fixed for native platforms. */ |
| 350 | int |
| 351 | ppc_sysv_abi_broken_use_struct_convention (int gcc_p, struct type *value_type) |
| 352 | { |
| 353 | if ((TYPE_LENGTH (value_type) == 16 || TYPE_LENGTH (value_type) == 8) |
| 354 | && TYPE_VECTOR (value_type)) |
| 355 | return 0; |
| 356 | |
| 357 | return generic_use_struct_convention (gcc_p, value_type); |
| 358 | } |
| 359 | |
| 360 | /* Structures 8 bytes or less long are returned in the r3 & r4 |
| 361 | registers, according to the SYSV ABI. */ |
| 362 | int |
| 363 | ppc_sysv_abi_use_struct_convention (int gcc_p, struct type *value_type) |
| 364 | { |
| 365 | if ((TYPE_LENGTH (value_type) == 16 || TYPE_LENGTH (value_type) == 8) |
| 366 | && TYPE_VECTOR (value_type)) |
| 367 | return 0; |
| 368 | |
| 369 | return (TYPE_LENGTH (value_type) > 8); |
| 370 | } |